MOSUL, Iraq (Reuters) -- A car bomb killed five Iraqi policemen and a Kurdish Peshmerga fighter near the northern city of Mosul on June 29, police sources said, a day before U.S. combat troops withdraw from urban centres.

Most Iraqis are hailing the U.S. pullback from towns and cities as a milestone on their country's road to sovereignty six years after the U.S. military invaded to topple Saddam Hussein.

But a string of bombings in Baghdad and northern Iraq in recent days, including two of the bloodiest attacks for more than a year, have shaken confidence in their security force.

Police sources said the car bomb was discovered on June 29 at a parking lot in the mostly Christian town of Hamdaniya, about 40 kilometers east of Mosul. They said it detonated as the officers sealed off the area. Three civilians were also wounded.

Hamdaniya is controlled by Kurdish Peshmerga forces.

Two big bombings in Baghdad and near the northern city of Kirkuk in recent days killed more than 150 people between them. U.S. and Iraqi officials have warned that they expect the number of attacks to increase as the U.S. troops pull back, and also in the run-up to a parliamentary election next January.

Prime Minister Nuri al-Maliki said on June 27 the U.S. withdrawal sent a message to the world that Iraq could handle its own security. The government trusted its forces to defeat Al-Qaeda militants and criminal gangs, he added.